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"EXC_BAD_ACCESS" error while trying to use pointer classes :s

Apr 16, 2012 at 7:30pm
emperorvinayak (6)
SO for my assignment, I had to make a matrix class, and using pointers, make the user enter a matrix, and then run the program to copy that matrix into another object and display both identical matrices. I have to use pointers for both matrices. Here's the code: 
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#include <iostream>
#include <fstream>
using namespace std;

class matrix
{
private:
    int rows;
    int cols;
    double** matrixPtr;
public:    
    matrix();
    matrix(int, int);
    matrix(int, int, double);
    matrix& operator =(matrix&);
    friend istream& operator >>(istream&,matrix&);
    friend ostream& operator <<(ostream&, matrix);
    double initial;

    //~matrix();
};


istream& operator >>(istream& getdata,matrix& array)
{
    if (array.matrixPtr!=0) 
    {
        for (int i = 0; i< array.rows; i++)
        {
            delete [] array.matrixPtr[i];
        }
        delete[] array.matrixPtr;
    }
    getdata >> array.rows >> array.cols;
    array.matrixPtr = new double* [array.rows];
    for (int i = 0; i<array.rows; i++)
    {
        array.matrixPtr[i] = new double[array.cols];
        for (int j= 0; j<array.cols; j++)
        {
            getdata >> array.matrixPtr[i][j];
        }
    }
    return getdata;
}

ostream& operator <<(ostream& showdata, matrix array)
{
    
    for (int i = 0; i<array.rows; i++)
    {
        for (int j=0; j<array.cols; j++)
        {
            showdata << array.matrixPtr[i][j] << " ";
        }
        showdata << endl;
    }
    return showdata;
}

matrix& matrix::operator =(matrix& array2)
{
    if (!array2.matrixPtr==NULL) 
    {
        for (int i = 0; i< array2.rows; i++)
        {
            delete [] array2.matrixPtr[i];
        }
        delete[] array2.matrixPtr;
    }
    
    
    array2.rows=rows;
    array2.cols=cols;
    array2.matrixPtr = new double* [array2.rows];
    
 for (int i = 0; i<rows; i++)
 {
    matrixPtr[i] = array2.matrixPtr[i];
 }
  for (int i = 0; i<rows; i++)
   {
       for (int j = 0; j<cols; j++)
       {
        array2.matrixPtr[i][j] = matrixPtr[i][j];
       }
   }
    return array2;
}

matrix::matrix()
{
    rows=0;
    cols=0;
    matrixPtr=NULL;
}

matrix::matrix(int row, int col)  
{
    rows= row;
    cols=col;
    matrixPtr = new double*[rows];
    for (int i = 0; i<rows; i++) 
    {
        matrixPtr[i] = new double[cols];
    }
    
    for (int i=0; i<row; i++)
    {
        for (int j=0; j<col; i++)
        {
            matrixPtr[i][j]=0.0;
        }
    }
    
}


matrix::matrix(int row, int col, double ini)
{
    ini = initial;
    for (int i=0; i<row; i++)
    {
        for (int j=0; j<col; i++)
        {
            matrixPtr[i][j]=initial;
        }
    }

}

int main()
{
   matrix thematrix, matrixreloaded;
   
    cout << "Enter the Number of Rows and Columns: ";
    cin >> thematrix;
    cout << thematrix;
    thematrix = matrixreloaded;
    cout << matrixreloaded;
    return 0;

}
Edit & run on cpp.sh


The problem is in the assignment operator definition, in which the line " array2.matrixPtr[i][j] = matrixPtr[i][j];" gives an error saying "Thread 1: Program received signal: "EXC_BAD_ACCESS" "

Any help would be greatly appreciated! :)
Last edited on Apr 16, 2012 at 7:32pm
Apr 16, 2012 at 8:05pm
ne555 (10692)
Your assignment operator is backwards
Last edited on Apr 16, 2012 at 8:05pm
Apr 16, 2012 at 8:20pm
emperorvinayak (6)
Eh thanks man, But I guess that's not the only problem... My program is probably full of bugs... There are other things I'm trying to work around as well... :s like swapping stuff..

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